Chelate compound-containing compositions can form a complex with various metal ions and the like. Therefore, such compositions have been preferably used in various applications such as organic chelating agents, scale inhibitors, water treatment agents, detergent builders, bleaching assistants, masking agents, fiber treatment agents, additives for papers and pulps, cleaning agents for semiconductors, photographic chemicals, and soil modifiers. Such compositions have been desired to be in solid states for convenience of transportation and storage.
With respect to a conventional chelate compound-containing composition, disclosed is an aqueous solution composition containing an iminocarboxylic acid having a specific structure, in which the isomer ratio (D-form/L-form (molar ratio)) of the aspartic acid skeleton of the iminocarboxylic acid salt is 1/0 to 0.7/0.3 or 0/1 to 0.3/0.7, and the content of the iminocarboxylic acid salt is 40 to 70% by weight (for example, referring to Japanese Patent No. 2644977, on pages 1 and 2). For such an aqueous solution composition, there is no description that the iminocarboxylic acid salt is made into solid states.
With respect to the iminodisuccinic acid compound sinsolid states, disclosed are: a powdery builder composition containing an iminodisuccinic acid compound and an inorganic metal salt, the composition being free from stickiness and having easy handle ability (for example, referring to Japanese Kokai Publication No. Hei-09-104897, on page 2); a powder containing animinodisuccinic acid compound and having a moisture absorption rate of 20% by weight/day or less under a constant air temperature of 23° C. and a constant moisture of 65%, the powder may being granulated; and a powder containing an iminodisuccinic acid compound and an inorganic metal salt and having a moisture absorption rate of 20% by weight/day or less under a constant air temperature of 23° C. and a constant moisture of 65%, and the powder may being granulated (for example, Japanese Kokai Publication No. Hei-09-110813). However, there are no suggestions and disclosures about the solubility of these powders, and there was a room for contrivance how to prepare powders excellent in solubility. These powders are produced by adding acid, an inorganic metal salt such as zeolites, a surfactant, or the like for adjusting the pH. However, compositions free from such additives and capable of being preferably used in various applications have been desired.